1. Field
One or more embodiments relate to a technology for building a map regarding a peripheral environment using a distance measurement sensor, and more particularly, to a technology accommodating a mobile robot to build a grid map using a distance measurement sensor.
2. Description of the Related Art
In some sense, the term “robot” has previously been considered an automaton in which mechanical equipment is installed, e.g., in a generally human shaped form to allow hands, feet, body, etc., thereof to operate automatically as if they were those of a human. However, the term “robot” also extends to any arbitrarily-shaped automaton that can perform given tasks automatically, for example.
Specifically, in the case of a mobile robot, its application range is expected to be extended so it can perform tasks in a desired location, for example, in severe environments or in dangerous regions. The concept of a home mobile robot, such as a cleaning robot, which helps with household chores while wandering about inside the house, has also been popularized.
In order for a mobile robot to perform its tasks while wandering about automatically, for example, it is desirable to make the mobile robot recognize its peripheral environment. The robot's recognition on a peripheral environment generally depends on a map. An example of such a map is a grid map where a corresponding peripheral space is partitioned by same-sized squares indicating whether an object exists in each square. A robot may create such a grid map regarding its peripheral environment using a distance measurement sensor, for example.
The distance measurement sensor may measure distances from itself to peripheral objects and output predetermined voltages, for example, based on the results of the measurement. The robot may, thus, create a grid map using the example output voltages. However, in the case where certain output voltages correspond to the same distance value in the distance-voltage characteristics of the distance-voltage sensor, as further explained below, the output from distance measurement sensor makes it unclear as to which distance value represented by the output voltages is the correct distance value when creating a map, which lowers the accuracy of the created map.